Reactivity of couplers incorporated in photographic emulsions



Unite States Patent REACTIVITY OF COUPLERS INCORPORATED IN PHOTOGRAP HIC EMULSIONS Arnold Weissberger, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed July 29*, 1957, Ser. No. 674,621

7 Claims. (Cl. 96-55) This invention relates to photography and particularly to the development of incorporated coupler photographic emulsions.

When color couplers are incorporated inphotographic emulsions as described in Jelley and Vittum US. Patent 2,322,027, one of the disadvantages is that a large amount of inert solvent is introduced to the emulsion and this tends to decrease the physical hardness of the emulsion layer. It has therefore been proposed to reduce to a minimum the amount of coupler solvent incorporated in th emulsion layer, and one method of accomplishing this is described in Fierke and Chechak US. Patent 2,801,171. However, when the amount of coupler sol vent is reduced, the reactivity of the coupler is also reduced, audit has been found desirable to incorporate a solvent suchas benzyl alcohol in the developing solu tion for the purpose of increasing the reactivity of the coupler. This method does not always increase the coupler reactivity and, therefore, the resulting dye density to the desired degree, and a greater increase in dye density 7 would be desirable,

Ihave found that a considerable increase in dye density is obtained upon'd'evelopment of, incorporated coupler emulsions, particularly emulsions in which the coupler is soluble in a solvent which is dispersed in the emulsion layer, by adding to the color developing solution a hydroxy compound of the class of p-alkylpheno1s' in which the vallsyl group contains from 1 to 5 carbon atoms, and n-octyl alcohol. Suitable compounds are p-n-arnylphenol, p-cresol, p-tert-amylphenol, p-sec. butylphenol and n-octyl alcohol. V

The concentration of the p-alkylphenol or other hydroxy compound in the developer should-be from about 0.1 gram to about grams per liter. A preferred amount is about 1 gram per liter of developer.

My invention is useful 'with emulsions containing any of the couplers described in Jelley and Patent 2,322,027 or 'Fierke and Che'chak U'.S.Patent 2,801,171. The following couplers are typical of those which may be incorporated in the emulsion.

5. N-(4 benzoylacetaminobenzenesulfonyl) N (7- phenylpropyl)-p-toluidine (U.S. Patent 2,298,443). 6. 1-(2,4,6-trichloropheny1)-3-{3-[a-(2,4 di n amylphenoxy) -acetamido] benzamido}-5 -pyrazolone. 7. l-(p-tert. butylphenoxy)phenyl-3-u-(p-tert. butylphenoxy-propionylarnino)-5-pyrazolone (U.S. Patent 2,369,489).

"ice

amylphenoxyacetamido)benzamido] 5-pyrazolone (U.S. Patent 2,600,788).

My invention will now he further illustrated by reference to the following specific examples.

Example 1 One hundred grams of couplers Nos. 1 to 7 were each dissolved in 250 cc. of ethyl acetate at the reflux tem perature of ethyl acetate. The solutions were poured into a solution containing 800 cc. of 10% gelatin solution and cc. of 5% Alkanol B solution (sodium triisopropyl naphthalene sulfonate) and then milled five times in a colloid mill. Fifty cc. of 'water was used to rinse the mill. The dispersions were set up on a chilled plate at 40 F., noodled and air-dried at 78 C. and 50% relative humidity.

Eight grams o e ch o these dispersions ere a ded to separate portions of a gelatino-silver halide emulsion containing approximately 0.046 mol of silver halide. After coating the emulsions on film support, the emulsions were exposed and processed in a developer of the following composition:

Grams 4-amino-N-ethyl-N- ,B-methanesulfonamidoethyl m-toluidine sesquisulfate monohydrate 5 Sodium sulfite, anhydrous 2 Sodium carbonate (monohydrate) 50 Sodium hydroxide 0.8 Sodium bromide .86

Water to 1 liter.

A second series of the emulsion coatings was exposed and developed in the same developer to which had been, added 1 gram per liter of benzyl alcohol, and a third series of the coatingswas exposed and developed in the developer to which had been added 1 gram per liter of p-n-amylphenol instead of benzyl alcohol. In each case the maximum density of the resulting dye image was read through a complementary color filter, and the. fol, lowing maximum density readings were obtained:

. ,Wlth With .de- With de- Couplers blank veloper velop'er Developer benzyl" p-n-amylalcohol phenol Example 2 The emulsion coatings of Example 1 were exposed and developed in a developer of the following composition:

Water to 1 liter.

Samples of the coatings were also exposed and developed in a developer of the same composition to which had been added 1 gram per liter of p-n-amylphenol.

The maximum density foreach dye image was obtained as above, and the following results were noted:

Developer Couplers Developer p-n-amylphenol 1. 80 2. 20 l. 87 l. 50 1. 34 2. 02 0. 50 2. 18 0. 52 2. 32 1. 48 l. 88 0. 8 1. 8

Example 3 Devel- Devel- Devel- D evel- Developer Deveioper oper p oper Coupler oper p-amyl oper n-octyl tert.an1- -sec.-

phenol p-cresol alcohol ylplienol utylphenol These density readings show that in every case the p-alkylphenol or n-octyl alcohol has produced an increased dye density, and in nearlyv every case, the dye density obtained with my compounds is' greater than that obtained with benzyl alcohol in the developer.

It has also been found that the compounds of my invention are of value for incorporation in developers in which the coupler is incorporated in the developing solution. When used with developers of this type, there is a great increase in dye density, particularly in the denser regions of the scale. The p-alkylphenols may also be incorporated in black-and-white developers.

The couplers or folor-forming compounds used in the process of my invention are of the type which couple upon development with the oxidation product of primary aromatic amino developing agents.

It will be understood that my invention is to be taken as limited only by the scope of the appended claims. A What I claim is: I

1. An aqueous photographic color developing solution capable of producing dye images of increased density, comprising an aromatic amine developing agent containing only two amino groups, said amino groups being in para relationship and at least one of said amino groups being a primary amino group, and from 0.1 to grams 4 per liter of solution of a hydroxy compound selected from the class consisting of p-alkylphenols containing from 7 to 11 carbon atoms, in which the alkyl group contains from 1 to 5 carbon atoms, an n-octyl alcohol.

2. An aqueous photographic color developing solution capable of producing dye images of increased density, comprising an aromatic amine developing agent containing only two amino groups, said amino groups being in para relationship and at least one of said amino groups being a primary amino group, and from 0.1 to 15 grams per liter of solution of a p-alkylphenol containing from 7 to 11 carbon atoms, in which the alkyl group contains from 1 to 5 carbon atoms.

3. An aqueous photographic color developing solution capable of producing dye images of increased density, comprising an aromatic amine developing agent containing only two amino groups, said amino groups being in para relationship and at least one of said amino groups being a primary amino group, and from 0.1 to 15 grams per liter of solution of p-n-amylphenol.

4. An aqueous photographic color developing solution capable of producing dye images of increased density, comprising an aromatic amine developing agent containing only two amino groups, said amino groups being in para relationship and at least one of said amino groups being a primary amino group, and from 0.1 to 15 grams 'per liter of solution of p-cresol.

5. An aqueous photographic color developing solution capable of producing dye images of increased density, comprising an aromatic amine developing agent containing only two amino groups, said amino groups being in para relationship and at least one of said amino groups being a primary amino group, and from 0.1 to 15 grams per liter of solution of p-tert. amylphenol.

' 6'. An aqueous photographic color developing solution capable of producing dye images of increased density,,- comprising an aromatic amine developing agent containing only two amino groups, said amino groups being in para relationship and at least one of said amino groups being a primary amino group, and from 0.1 to 15 grams per liter of solution of p-sec. butylphenol. 7. An aqueous photographic color developing solution capable of producing dye images of increased density, comprising an aromatic amine developing agent containing only two amino groups, said amino groups being in para relationship and at least one of said amino groups being a primary amino group, and from 0.1 to 15 grams per liter of solution of n-octyl alcohol.

References Cited in the file of this patent UNITED STATES PATENTS 2,486,440 Schmidt et a1. Nov. 1, 1949 2,570,116 Gunther Oct. 2, l= 2,594,917 Gunther Apr. 29, 1952.- 2,835,579 Thirtle May 20, 1958 

1. AN AQUEOUS PHOTOGRAPHIC COLOR DEVELOPING SOLUTION CAPABLE OF PRODUCING DYE IMAGES OF INCREASED DENSITY, COMPRISING AN AROMATIC AMINE DEVELOPING AGENT CONTAINING ONLY TWO AMINO GROUPS, SAID AMINO GROUPS BEING IN PARA RELATIONSHIP AND AT LEAST ONE OF SAID AMINO GROUPS BEING A PRIMARY AMINO GROUP, AND FROM 0.1 TO 15 GRAMS PER LITER OF SOLUTION OF A HYDROXY COMPOUND SELECTED FROM THE CLASS CONSISTING OF P-ALKYLPHENOLS CONTAINING FROM 7 TO 11 CARBON ATOMS, IN WHICH THE ALKYL GROUP CONTAINS FROM 1 TO 5 CARBON ATOMS, AN N-OCTYL ALCOHOL. 